Computing machine



Jan. 28, 1941. w. w. LANDSIEDEL COMPUTING MACHINE Filed April 6, 1936 6Sheets-Sheet 1 INVENTOR Winn e WLANDS/EDEL ATT RNEY Jan. 28, 1941. w. w.LANDSIEDEL COMPUTING MACHINE mvzm-oa WALTER WLANDJIEDEL Filed April 6,1956 Jan. 28, 1941. w. w. LANDSIEDEL COMPUTING MACHINE Filed April 6,19:56

' \N VENTO R WZLTEQ WLANos/ma Jan. 28, 1941. w. w. LANDSIEDEL COMPUT ING MACH INE Filed April 6, 1936 6 Sheets-Sheet 4 lNVEh lTOR Wu TE/a WLMos/051. 74

AT TO R N EY 1941- w. w. LANDSIEDEL 2,229,980

COMPUTING MACHINE Filed April 6, 1936 6 Sheets-Sheet 5 HEICICIHCH II II) N M INVENTOR W405? WLANDSIEDEL Jan. 28, 1941. w. w. LANDSIEDEL2,229,980

COMPUTING MACHINE Filed April 6, 1936 6 Sheets-Sheet 6 Fici. 10

' INVENTOR Wham W LANDS/[DEL Patented Jan. 28, 194 1 PATENT OFFICECOMPUTING MACHINE Walter W. Landsiedel, Norwomlj Ohio, assignor to-Remington Rand Inc., Buihlo, N. Y., a corporation of DelawareApplication April 6, 1936, Serial No. 73,020 4 Claims. (Cl. 235-60) Myinvention relates to computing machines, and it resides in certainimprovements, features of construction and combinations and arrangements of parts, all of which will be fully set forth herein andparticularly pointed out in the claims.

The immediate and specific object of the present invention was toimprove the small portable and inexpensive ten-key adding and listingmachine shown in patents to T. O. Mehan, Nos. 1,835,170, 1,876,719 and1,899,444.

The particular object had in mind, in the present invention, was toincorporate into the machine a small operating motor and'to adapt themechanism of the machine to operation by such a motor at a much higherspeed than that at which the machine had formerly been operated. Indoing this, improvements were made which can -be modified considerablyfrom the specific form shown, and which are applicable to othermachines. The basic idea behind most of these improvements was toincrease the speed of operation while preserving and perhaps improvingthe qualities of reliability and certainty of operation. The drawingswere made from a specific machine which, by holding down the motor bar,may be operated at a speed considerably above 140 cycles a minute andwhich machine is nevertheless small and light and inexpensive.

Among the other features incorporated in the present machine may beenumerated the follow- (1) The provision of an improved adding rack andcarrying slide interlock.

(2) The provision of a new and motor drive mechanism.

(3) The provision of novel and effective nonprint and non-line spacemechanism, and of improved single and double line space mechanism forthe I platen.

My invention, therefore, has for its object to produce an improvedcomputing and recording machine in respect of the matters aboveindicated, and of others which will be apparent from the followingdescription;

In the accompanying drawings, wherein like reference charactersrepresent corresponding parts in the various views:

Fig. 1 is a right-hand side elevation of the machine, the case of whichis shown in vertical section, and with parts removed or shown in sectionor broken away.

Fig. 2 is a fragmentary right-hand side elevation showing the motorswitch in closed position and associated parts in normal position.

Fig. 3 is a fragmentary right-hand side elevation similar to Fig. 2 butshowing the motor drive crank, motor drive arm and associated parts asthey will appear when half way through the return stroke of an operatingcycle of the machine. 5

Fig. 4 is a front to rear vertical section through the machine with someparts omitted, other parts partially broken away and still others shownin elevation.

Fig. 5 is a partial right-hand elevation showing 10 the delayed hammerfiring mechanism and its relation with the motor drive mechanism, thecase and part of the base appearing in vertical section.

Fig. 6 is a top or plan view of the rear or motor 15 end of the machinewith the case and other parts removed to clearly show the electric motorand some of the mechanism driven thereby.

Fig. 7 is a view similar to Figs. 2 and 3, but showing the parts at theend of the forward 20 stroke.

Figs. 8 and 9 are detached diagrammatic views illustrating the addingrack and carrying slide interlock.

Fig. 10 is a front elevation of the machine with 25 the cover and baseplates removed.

In the accompanying drawings I have shown only so much of said machineas may be necessary to arrive at an understanding of my presentinvention in its embodiment therein. 30

From a consideration of Figs. 1, 4, 6 and 10, it will be seen that theframe of the machine by which the various working parts are supportedcomprises left and right outer frame plates H38 and 101, respectively,united by cross bars I02 35 and I03, by the upper key board plate I04and by the base or bed plate I05; also, left and right inner frameplates 28!, 282, between which the register and printing mechanisms aremounted.

The computing and printing operations determined by the set-up of thedigit keys I06, are controlled in the present instance by the motor barHll, Fig.1, mounted at the right-hand side of the machine and which barcontrols the electric motor I08 (Fig. 6) which drives the main rockshaft [09, though obviously said shaft may be hand. driven by the usualhandle carrying crank shown in Patent No. 1,899,444.

The digit keys I06 (Fig. 4) are arranged above the upper keyboard plateI04; the stem of ea'ch key passing through a guide slot in said plate. Areduced depending portion of each key stem passes through a guideslot'in a lower keyboard plate H4 and is surrounded by a coiledexpansion return spring H5 (Fig. 4). Eachdigit key 55 stem also has anoffset depending tappet portion II8 (Fig. 10) that projects downwardlythrough a guide opening in the plate II4, all of the tappets II8 beingarranged in a single row fore and aft of the machine. v

The pin carriage, which is designated as a whole by the referencenumeral II1, (Fig. 4) is supported and guided on the cross bars I02 andI03 for movement transversely of the machine beneath the lower keyboardplate 4. This carriage carries rows of pins II8 (nine rows in thepresent instance) with nine pins in each row. Each of these pins ismounted in the carriage for limited vertical movement therein from anupper ineffective position as shown in Fig. 8 to a lower effectiveposition, shown by #4 stop in Fig. 9. The parts are so constructed thateach pin remains in either position to which it may be shifted untildisplaced therefrom, as is well known in the art. When the carriage isin its normal or initial right-hand position (Fig. 10) the left-handfore and aft row ,of pins H8 is beneath the tappet portions II8 of thedigit keys sponding tappet II8.

As the keys are depressed the carriage moves step-by-step from itsinitial right-hand position, and the fore and aft rows of pins II8 arebrought successively into register with the row of depending tappetportions I I8 of-digit keys I08, each pin II8 of a row being directlybeneath the corre- When the main shaft I09 is actuated, each depressedpin'will arrest the rearward motion of corresponding adding rack II9(spring impelled by its associated spring I20) in its proper position todetermine the amount .to-be registered and recorded. On the returnstroke of the machine, carriage H1 is automatically returned to theright (as viewed in Fig. 10) beyond its initial position, or to aposition known as the overthrow position, and eventually comes to restin the normal position. The frame plate IOI. has an opening M, Fig. 1,to allow parts I23 and I28 to move tothe overthrow position."

During the return movement of the carriage the lowered effective stoppins II8 are brought successively into contact with a fixed cam plate asdisclosed in Patent No. 1,899,444 thus causing the pins to be restoredupward to ineffective position on the pin carriage by a camming action.The return movement of the carriage may also be effected at any timewith like effect by the aid of the usual correction key I2I, as pointedout in Patent No. 1,876,719.

The step-by-step feed movement of the pin carriage is controlled in thesame manner as disclosed in the above mentioned Patent No. 1,899,444 butwill be explained again in detail in order to fully disclose the action,operation, and advantages of the digit key pin carriage overthrow lock.Power is exerted to move the carriage from the right to left by a springI22 (Fig. 10) anchored at one end, to the left side frame plate I00, andconnected at its opposite end to an arm I23, as shown in Patent No.1,899,444. Said arm is fast at its lower end on a rock shaft I24,journaled in a bracket on the base I05, the upper end of the arm beingpivoted at I25 to one end of a link I28, the opposite end of which ispivoted at I21 to a bracket I28 formed integral with feed rack I29.

M otoa" drive Referring now to the motor drive and especially toFigs. 1,2, 3, 5 and 6, the small electric motor I is secured to the base I anddrives a ratchet disk I80, (which is an element of a onerevolutionclutch) through speed-reduction gear ing consisting of a pinion I11(Fig. 6) on the armature shaft I18, which meshes with a gear I fast witha pinion I19. which latter meshes with a gear I80 fast on the shaftI82'on which said ratchet I88 is secured. Th driven member of saidclutch consists of a drive crank or disk I89 (Fig. 5) carrying a clutchpawl 200 adapted for engagement with and disengagement from the ratchetI88. Said disk carries a stud or wrist pin 242 and roller 243 playing ina slot 244 in a two-armed drive lever 245 which in turn carries a stud248 and roller 249 (Fig. 5) playing in a radial slot 250 in an arm 25Ion the main shaft I09. The construction is such that each rotation ofdisk I 89 imparts to said main shaft a complete oscillation consistingof a forward and a return stroke. The base I05 has integral therewith anupright wall I8I which serves to support the ratchet shaft I82 andvarious control devices.

As clearly shown in Fig. 5, clutch pawl 200 is pivotally mounted on theouter face of drive crank I88 at 201, and has a finger 202 forengagement with the ratchet I88. A spring 204 lying in an opening. 201in crank I 89, urges the" finger 202 towards the ratchet I88. When thedrive crank I89 is in the normal position as shown in Fig. 5 a. shortarm 205 of the clutch due to the reaction of spring 204 for the lock.pawl 200 is prevented by back stop 2 which is like a pawl pivoted at I84to the wall II and controlled by a spring 2I3. The pin 208 extendsthrough and projects leftward from the disk I 89. where it is engaged bythe end of the stop pawl 2. Control arm 2I0 is bail-shaped and each ofthe arms of the bail pivots upon a stud I88 mounted on the outer side ofwall I8I. The control arm 2I0 has an upwardly projecting arm 2I8supplied with a keeper stud 2" on which the' eye of a=wire link 2I9 ispivoted and is retained thereon by keeper 220. The other end of link 2I9terminates in an eye which is pivoted on a keeper-stud 222, carried bythe upper end of a control bell crank 223, an arm of which carries aroll 22I underlying the stem of the motor bar or key I01. The controllever 2I0 is drawn upward by a spring 23I. The construction' is suchthat if said lever be tripped momentarily as by depressing the motor barI01, the clutch pawl 200 will bedrawn into engagement as shown in Fig.2, and, if ratchet I88 is rotating,'crank disk I89 will revolve (Fig.3),

pawl 200 is held between a pin 208 carried on trip lever 2I0 will returnto normal position and 4 at the end of one rotation of disk I89, saidlever will be struck by arm 205, forcing pawl 200 out of engagement, andarresting the rotation of crank disk I89. The stop pawl 2 will snap intoengagement with the stud 208 and hold the crank disk against backwardturning.

The motor may, if desired, be controlled by a hand switch and be allowedto run continuously while the machine is in use, but it is preferable tohave the motor energized only during each cycle of operation, itscircuit being closed automatically when the control lever 2I0 istripped, and broken just before the crank disk I89 completes itsrotation. To this endthe motor circuit includes two fixed contacts 239(Figs. 1, 2, 3 and 5) mounted on an insulating support 240 secured tothe top of the base wall I8I, and means are provided to connect thesetwo contacts with a conductor 236 at the proper times. This conductorhas the U-shape shown in Fig. 6 and it carries on its elastic arms twocontacts 238 for cooperation with contacts 239. i

The conductor 236 is riveted at 231 to a piece of insulating material236 which is secured to the horizontal cross bar of a bail-shapedcontact arm 228 which straddles wall I8I, and is pivotally mounted upona stud or short shaft I83. The structure is urged clockwise in thedrawings by the spring 23I, the upper end of which is connected to theouter branch 229 of said contact arm. The control arm 2I0 is theright-hand branch of a bail, the left-hand branch of which is an arm 225having at its end two stepped shoulders 226 and 221 (Fig. 3). The arm229 terminates in a tail 230 which is normally pressed by spring 23Iagainst the lower step or shoulder 226, which thus holds the contacts238 away from contacts 239, as best shown in Fig. 1.

When the control arm 2I0 is tripped as shown in Fig. 2, arm 225 is swungdownward, tall 230 escapes from step 226, swings forward and limits onstep 221, as best' shown in Fig. '1. This clockwise rotation of thecontact arm closes the motor circuit at 238, 239 and starts the motor.

In order tO break the motor circuit positively, the crank disk I89 has aprojecting cam nose I91 which, just before the completion of a rotationof said disk, strikes a stud I98 on the arm 229 and forces said armtoward the rear of the machine, raising the contacts 238. Up to thistime thetail 230 resting on top of step 226, had held the control arm2III depressed, as shown in Fig. 3. The counter-clockwise swinging ofarm 229 releases control arm 2 III which, unless the lever 223 is heldin operated position, instantly snaps into the pathof arm' 205 of pawl200 and stops the crank disk 229 as above described. If the control arm2! is held out by any means, the machine will execute a succession ofcycles. The motor circuit will be broken at the end of each cycle asjust described, but the contact arm will immediately swing back tocircuit-closing position and the motor will not stop.

The type bars I53 (Fig. 4) are guided for vertical sliding movement byupper fixed combs 263 and 264. Below said comb plates the type bars arevertically slotted at 265 to fit in notches formed in a fixed plate 266and over a fixed bar 261. The type 268 may be slidably secured to thebars I53 in any suitable manner as is well known in the art. Racks 269on the front edges of the type bars I53 are in mesh with pinions 210which are freely mounted in suitable spaced relation on a fixed shaft21I. The pinions 210 are also in mesh with adding racks H9 and thustransmit the differential motion of the adding racks to the type bars.

The type hammers 212 are freely pivoted on a shaft 213 and urged to typestriking position by means of springs 214 which at one end are anchoredto the rod 215 and at the other end se-' cured to the rearwardlyprojecting ears 216 integral with the hammers. The hammers 212 arenormally held in their forward position by the engagement of a sear 211over their toes 218. The ends of the sear 211 terminate in a pair ofoppositely disposed bail arms 219 which are fixed to the shaft 288 justinside the center frame plates 28I and 282 respectively.

There are some matters of timing that are worthy of note. It is desiredto keep the machine as small, light and portable as may be, and it is,therefore, for that and other reasons desirable to use a small motor.The load on the motor varies considerably in diiferent parts of thecycle and the connections are so designed as to give the motor a higherleverage on the mechanism at the times of high load than at the times oflow load. There is but little load on the motor during the forwardstroke of the shaft I09.

It will be noted that the slot 244 (Figs. 1 and 5) in the lever 245 isas to its outer portion about radial of the lever arm and when themachine is standing in its normal position shown in Fig. 1, the roll 24:is m that portion of the slot which is tangent to the orbit of the saidroll. The construction is such that the extreme swinging motion of thelever 246 is from the point where this radial slot is tangent to theorbit of the roll 243, as shown in Fig. 1, to the point where this sameline is tangent to said orbit in its lower position, as shown in Fig.'1. It will be perceived that this is about 120 of the rotation of thedisk I89. During this period, the roll ,is moving in the part of theslot244 nearest the pivotal center I85, and is, therefore, rocking the lever245 much more rapidly than during the remaining two-thirds of therotation of said roll, at which time the roll is in the outer portion ofthe slot and has a longer leverage on the lever 245. It is during thisperiod that the heavy work is encountered by the motor in restoring theparts and stretching the springs of the differential slides.

Not only is the inner end of the slot 244 nearer to the pivot I65, butthis end of the slot is also inclined upward out of the radial, so thatas the roll 243 moves through about its first 60, it

- swings the lever 245 through more than half of the full motion of thatlever. In the next 60 of rotation, the roll is running down the inclineof the slot and the lever 245, therefore, moves less rapidly. It isduring this time that the roll 33I,

which controls the differential slides is moving in the inclined part ofits cammed groove and drawing the restoring bar 328 toward the rear ofthe machine.

When the roll 243 reaches the position shown in Fig. '1, which is theend of the forward stroke of the operating shaft I09, the roll issubstantially in the curved part of the 'slot 244 where the two inclinedbranches of said slot meet. There is at this point, therefore, a periodof somewhere near 30 of rotation of the disk I89, where there is almostno motion at all of the lever 245 and the shaft I09. It is at thisperiod that the adding racks and type bars have been arrested by theirstops and this pause in the operation of the machine gives them a momentin which to quiet down any vibration into which they may have been setby the arrest of their motion.

Adding rack and carrying slide interlock with opposed spaced apart slotsto receive the adding racks and thus maintain them in suitable spacedrelation.

A carry slide 319 (as best shown in Figs. 8 and 9) having slots 320 and32!, is slidably secured toeach adding rack H9 by a pair of shoulderrivets 322 which extend freely through the slots 320, 32I, and are fixedin the adding racks. A spring 323 (received by the openings 324, 325 inthe adding rack H9 and. carry slide 3I9 respectively) has one endsecured to the slide 3| 9 and its other end secured to the adding rackH9 as clearly shown in Figs. 4, 8 and 9. This spring tends to move theslide 319 to its rearward position on the adding rack I I9, which effectis utilized in transferring operations in a manner soon to be described.As before mentioned a tensil spring I has one end secured to a dependingtoe 326 at ,the forward end of the slide 3| 9 and has its other endanchored to a fixed rod 215 at the rear of the machine. This springtends to move the slide and its associated adding rack rearwardly as aunit. The slide 3I9 is normally restrained from such rearward movementby the engagement of its rearward toe 321 with the restoring rod 328,the ends of which slide in the slots 329329 in the center frame plates28I and 282.

In order to reciprocate the restoring rod 328, a shaft 333 (Figs. 4 and6) journaled in the frame plates '20I and 282, has fast thereon aright-hand arm 332 just outside plate 28I and a left-hand arm 334 justinside of plate 282. Upon the forward stroke or counter-clockwisemovement of main shaft I09 as viewed from the right-hand side of themachine the cam plate 3I5 fast on said shaft is rotatedcounter-clockwise and. through engagement of its slot 330 with a roller33I carried by the right arm 332 (see Figs. 1, 4 and 6-) rocks shaft 333and its two arms counter-clockwise also. Links 335-335 connect the lowerends of arms 332, 334 with the restoring rod 328. It will therefore beseen that upon the forward stroke of the machine the restoring rod 328will be moved rearwardly and carry-slides 3I9 will be free 'to follow,being moved .by their tension springs I20 until the projections 336strike the pins H8 (as best shown in Figs. 4, 8 and 9) which have beenpreviously depressed by the actuation of the digit keys I06, and uponthe return stroke of the main shaft the rod 328 will restore the racksto initial positions.

In order to adapt the mechanism to a higher speed than hand operation,certain changes from former constructions have been made in thecarry-slide 3I9 and its connection with the rack bar H9. In the stopcarriage H1, at the left of the series of stops H8, there is in thismachine the usual flap or stop bar 286 (Fig. 10)having its forward edgein alignment with the zero stops H8, this device having for its functionto hold against movement all of those rack bars H9 at the left of thehighest digit being added. In the machine heretofore the lug which wasarrested by this stop bar and by the stops I I8 consisted of an upwardlyprojecting finger integral with the bar H9. When the parts were restoredto normal position, these fingers lay immediately in front of the zerostops, or rather, of the flap 286 above referred to. The restoring bar328 does not act on the bars H9 directly, but acts on the slides 3I9which are connected with the bars I I9 by the springs 323. It was foundthat in very rapid operation by a motor, the bar H9 might lag behind theslide 3I9 in its restoring motion. In the last part of the return strokeof the mechanism, the carriage H1 is restored to the right, and it wasfound possible that in rapid operation a bar H9 lagging behind its slide319 might fail to get its stop finger out of the way of the stop fiap286 on the carriage and there would be a collision of the parts. Toprevent this in the present construction, the stop finger has beenremoved from the bar H9 and now consists of a finger 336 projectingupward-from the front end of the slide 3I9, and having an ear formedover to cooperate with the stops H8. Not only is this finger positivelyrestored by the bar 328, but in its normal position it stands somedistance in front of the stop flap so that there is no danger ofinterference such as above described.

Arresting the parts by a lugon the slide 3I9 introduced the possibilityof another trouble, viz., that of the overthrow of the bar H9,stretching the spring 323, when the slide 3I9 was arrested. To providefor this the parts have been modified so as to lock the bar H9 and slide3I9 together on their rearward movement. The rear end of said slide 3I9is ex- 'tended upward to-make a'heel 331, which, as

shown in Fig. 8, normally lies beneath a plate or lamination 338 securedto the side of the bar H9 and the slot 32I has been widened at its frontendto allow thisheel to move up behind said lamination when the slide3I9 moves rearward on the bar H9 as shown in Fig. 9. The spring 323tends to pull the bar H9 toward the front of the machine so that, whenthe restoring bar 328 first moves rearward, the slide 3I9 follows itindependently of the bar H9 until the front end of the slot 320 strikesthe shouldered rivet 322. The spring I20 being below said rivet thenturns the slide 3I9 upward at its rear end bringing about the lockingengagement referred to, with the result that, when the car 336 isarrested, the bar H9 cannot overthrow.

In order to restore the parts totheir normal relative positions, therear end of the slide 3I9 is extended into'a toe or finger 321, theupper edge of which is inclined and is contacted by the restoring bar328 which thus cams the rear end of the slide 3I9 down out of engagementwith the lamination 338.

Ihe particular point in the operation at which the overthrow of the rackH9 would be most harmful is that at which the slide is arrested by oneof the higher stops such as 1, 8 or 9, and especially the last. When therack H9 is arrested at that position in an adding operation, theregister wheels are very soon thereafter depressed into engagement withthe racks, and it is essential that the racks be accurately positioned,and that there be no overthrow, stretching the springs 323 at that time.In the case of smaller numbers the vibration of the racks would havetime to quiet down before the register wheels were engaged. In order torestore the slide 3I9, it is necessary that the bar 328 contact theinclined toe 321, but such contact may have some tendency to prevent theupward movement of the heel 331. For this reason the guide slots 329 forthe bar 328 are made in two levels con-' nected' by'an incline as shownin Fig. 4, the forward portion of each slot being at the lower level toinsure the disengagement of the heel 331, and the rear portion of eachslot being at the higher level in order that the bar 328 shall engagenot the inclined toe 321 but the vertical rear edge of the slide at thetime when the parts are arrested by one of the stops of higher value.

The line space mechanism for turning the platen 524 (Fig. 1) is operatedfrom the printing upstroke of said pawl, rub

hammer restoring bail and, therefore, does not operate when thenon-print key is in use. The right-hand arm 3l0 of this bail has pivotedthereto a link 525 which at its rear end has lost motion pivotalconnection with a bell crank 526, the horizontal arm of which haspivoted thereto the line space pawl 521, which acts on the ratchet 528against which it is pressed by a spring 530. The construction is suchthat when the bar 3I2 moves toward the rear in the forward stroke of theoperating shaft, the pawl 52'! moves upward to take hold of a new toothof the ratchet, and it moves downward to space the paper on the returnstroke following the printing. On the downstroke of thepawl 521, a studor roll 53l on the end of the pawl engages a tooth of the ratchet andcams the pawl out of engagement with the ratchet so as to leave theplaten free to be finger wheel 532. tent comprising a roll 533 mountedon a springpressed lever 534 and engaging the ratchet wheel teeth.

In order to provide for single and double spacing, an arm 535 is pivotedon the axle of the platen and has two notches 536 for engagement by theaxle of the roll 533. The construction is such that this lever can beset to either of two positions, where it will be retained by saidnotches. When set in the rear position shown in Fig. 1, the stud 53l-onthe pawl 521 will, on the against the rear edge of this lever and holdthe pawl out from one of the teeth of the ratchet, so that on the downstroke, the ratchetwill be turned only. one tooth. With this lever inits forward position, the pawl will not be so deflected, and it willengage a higher tooth, so that, on its down stroke, it will turn theplaten two teeth of the ratchet.

Various changes may be made in the details of construction andarrangement without departing from my invention.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In an adding machine, the combination of a register wheel, areciprocating rack for actuturned in either direction by a The platen isretained by a de- 1 ating said register wheel on its return movement, adifferential member connected to said'rack for relative sliding androcking motion, means on said member and rack for locking together saidmember and rack, and means acting during the initial movement ofsaidmember to cause first a sliding movement of said member relative tosaid rack, and then a rocking movement of said member into lockingengagement with said rack.

2. In an adding machine, the combination of a register wheel, areciprocatory rack for actuating said wheel, a differential memberhaving a lostlmotion connection with said rack and movable relatively tosaid rack for preventing overthrow of said rack, stops for arrestingsaid differential member, a restoring bar for said differ ential member,and means for guiding said restoring bar to effect movement of saiddifferential member from overthrow-preventing position to normal restposition.

3. In an adding machine, the combination of a register wheel, areciprocatory rack for actuating said wheel, a locking element on saidrack,

a differential member having a locking element and having a lost motionconnection with said rack, and' means for first moving said differentialmember for taking up the lost motion between it and said rack and foreffecting movement of one of said locking elements into locking relationwith the other of said locking elements during the initial movement ofsaid differential member.

4. In an adding machine, the combination of a register wheel, areciprocatory rack for actuating said wheel, a locking element on saidrack, a differential member having a locking element and having a lostmotion connection with said rack, means for first moving saiddifferential member for taking up the lost motion between it and saidrack and for effecting movement of one of said locking elements intolocking relation with the other of said locking elements during theinitial movement of said differential member, and a rod for returningsaid rack and member to normal and concomitantly effecting unlocking ofsaid locking elements.

WALTER W. LANDSIEDEL.

